Detection of quantitative trait loci for phosphorus deficiency tolerance at soybean seedling stage

Phosphorus deficiency is a primary constraint to soybean productivity in acid and calcareous soils. Our aim was to map quantitative trait loci (QTL) controlling phosphorus deficiency tolerance using 152 recombinant inbred lines derived from a cross between the P stress tolerant variety Nannong94-156 and the P stress sensitive variety Bogao. Five traits were used as parameters to evaluate phosphorus deficiency tolerance at seedling stage under different phosphorus levels in experiments 2005 and 2006. As a result, thirty-four additive QTLs were detected on nine linkage groups, with corresponding contribution ratios of 6.6-19.3%. There were three clusters of QTL found in genomic regions S506-Satt534 (on linkage group B2-1), Sat_183-Satt274 (on linkage group D1b + W), and Sat_185-Satt012 (on linkage group G). The locus flanked by Sat_183-Satt274 on linkage group D1b + W was coincident with four previously discovered QTLs with phosphorus efficiency. Another interesting locus flanked by Sat_185-Satt012 on linkage group G was detected across years. The identified QTL will be useful to improve the stress resistance of soybean against a complex nutritional disorder caused by phosphorus deficiency. In addition, more QTLs were detected under low phosphorus condition and some QTLs were detected that specifically expressed under different phosphorus levels. These particular QTLs could help provide greater understanding of the genetic basis of phosphorus efficiency in soybean.